(1) Field of the Invention
The present invention relates to an optical disc device and a tracking servo control circuit for the optical disc device and particularly to an optical disc device having an improved tracking servo control and a tracking servo control circuit for the optical disc device.
(2) Description of the Related Art
In the field of optical disc devices, densification of recording is developing as recording mediums evolve in the order of CDs (compact Discs), DVDs (Digital Versatile Discs), and BDs (Blu-ray Discs). A pitch of a track of discs for data recording is narrowing. For example, a pitch of a CD is 1.6 μm, a pitch of a DVD-R (Recordable) is 0.74 μm, and a pitch of a BD-R is 0.32 μm. Therefore, a tracking servo control may require higher accuracy to reproduce signals from an optical disc.
Japanese Patent Application Laid-Open No. H9 (1997)-7200 discloses a technique in which an offset is detected from an envelope of signal components of a light receiving element having a radially divided light receiving surface to compensate for a signal level of a push-pull signal.